Symmetric Response Magnetoresistance Sensor With Low 1/f Noise by Using an Antiphase AC Modulation Bridge

A new high-sensitive magnetic sensor which is referred to a symmetric response magnetoresistance (SRMR) proposed. This uses giant (GMR) elements have field response. An ac with frequency f applied the GMR in order modulate small detecting field. Due of MR element, carrier signal converted 2f and . By using full bridge circuit, where two pairs opposite phase field, components can be eliminated at differential output terminal bridge. Since this system converts range higher one, its noise level, dominated by 1/f noise, decreased. In study, SRMR antiphase modulation was fabricated investigated. The effect reduction suppression were confirmed circuit simulation based on element. full-bridge four dual-spin-valve fabricated. It that (2f components) reduced less than level (f components). increase found near f, may due slight asymmetry shown (MR)